Big Horn; Finch Prospect, Chistochina Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Big Horn; Finch Prospect	Prospect
Chistochina Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

The locality is in the Wrangell-Saint Elias National Park and Preserve.
Location: This prospect is on the north valley wall of Kuskulana Glacier. It is at an elevation of about 4,500 feet, 5,200 feet southwest of elevation 6940, and 1,700 feet from Kuskulana Glacier. The prospect is near the northwest corner of section 33, T. 2 S., R. 10 E. of the Copper River Meridian. This is locality 157 of MacKevett (1976); the location is accurate to within about 1,000 feet. Cobb and MacKevett (1980) included this prospect under the name 'Big Horn'.
Geology: The deposit at this prospect consists of bornite-, chalcocite-, and malachite-bearing veins and pods in strongly faulted Triassic Nikolai Greenstone (MacKevett, 1976). One disk-shaped bornite-chalcocite-quartz mass was up to 16 feet across (Moffit and Mertie, 1923; Van Alstine and Black, 1946). The deposits were explored by several short adits and numerous surface workings. The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Workings: The deposits were explored by several adits and surface workings.
Age: Cretaceous? The widespread deposition of copper in Triassic greenstone and limestone of the area is thought to have accompanied regional deformation and low-grade metamorphism in the Late Jurassic or Early Cretaceous (MacKevett and others, 1997). Copper-bearing minerals were deposited in the underlying Nikolai Greenstone at about 112 Ma (Silberman and others, 1980).
Alteration: Oxidation.

Commodities (Major) - Cu
Development Status: None
Deposit Model: Basaltic Cu (Cox and Singer, 1986; model 23)

Other Databases

Link to USGS - Alaska:	MC068

Other Regions, Features and Areas containing this locality

References